Ballmer was vague about when exactly Ozzie will leave. He’ll remain for “a while” while he transitions the teams and ongoing projects in his organization, Ballmer wrote. “Following the natural transition time with his teams but before he retires from Microsoft, Ray will be focusing his efforts in the broader area of entertainment where Microsoft has many ongoing investments,” he said.

Microsoft does not plan to replace him. “The CSA role was unique and I won’t refill the role after Ray’s departure,” Ballmer wrote.

He praised Ozzie’s work at Microsoft. “Ray has played a critical role in helping us to assume the leadership position in the cloud, and positioned us well for future success,” Ballmer said.

Ozzie joined Microsoft in 2005 as chief technical officer when the software giant acquired his company, Groove Networks. He was best known at the time for being one of the creators of Lotus Notes.